Fridge/relay wiring... have I got it right?

[paul_374300602]

I've just wired up an 's' type grey socket and a dual relay to my towcar. It seems fine and is charging the caravan battery and running the fridge as expected. However when I turn off the ignition the battery stops charging but the fridge light stays on. I can turn it off at the fridge switch but shouldn't it be dead once the engine stops running and the ignition is off?

I think I've wired it up correctly.Any thoughts?

Paul.

 

[antrimboy]

Paul, I remember reading on a previous posting that what you are getting is absolutely correct.The fridge light is on a separate circuit to the charging.

 

[ProfJohnL]

Hello Paul,

I think you have it incorrectly wired.

The fridge uses a lot of 12V current so it should only work on 12V when the engine is running, Similarly the Battery should only receive charge from the engine when the engine is running, so something is not installed or working correctly.

Don't forget that although you might not receive an electric shock from 12Vdc, the amount of current that a car battery can provide can easily cause wiring to overheat and set alight if a fault or short circuit occurs.

If you are unsure about the wiring I strongly suggest you contact a professions to sort it out for you.

 

[antrimboy]

http://www.caravantalk.org.uk/index.php?showtopic=10352&hl=fridge light
Paul, providing the above link works, I think you'll find that the fridge control panel and light operate from the caravan battery, but the fridge operates on a different circuit from the car.Try switching your caravan 12 volt system off and have a look at the fridge light.

 

[WatsonJohnG]

If its the fridge interior light and not the warning light then its OK

More recent Dometic and Thetford fridges need a permanent 12V supply from the caravan as well as the 12S to work the electronics.(there are 2 terminals on the Dometic clearly marked on the top of the fridge)

The 12V on tow operation is now thermostatically controlled

 

[paul_374300602]

Thanks for replies so far.

I think I mislead you on the first post. It's the light on the on/off switch on the fridge(not the interior) which is on even when the ignition is off indicating that the fridge is still connected and running from the car battery.When the car is unplugged from the van the fridge won't work on the caravan battery at all.(as is correct)I can of course switch it off but that seems to defeat the object of the relay. I followed the wiring diagrams and reckon it's wired correctly.It's a puzzle..

 

[WatsonJohnG]

If the light goes out when you unplug the 12S from the car then either you have a faulty relay or its wired wrong

Power should only be on pin6 the red wire when the engine/ignition is on

 

[WatsonJohnG]

If the light goes out when you unplug the 12S from the car then either you have a faulty relay or its wired wrong

Power should only be on pin6 the red wire when the engine/ignition is on

www.towitall.co.uk

 

[WatsonJohnG]

You could try swapping the feed from the twin relay to the 12S socket so that the green wire to pin 4 is going to pin 6 instead of the red wire and that would show if the fridge side is OK as you state that the charging side goes off with the ignition.

It would also show if the relay now used to the fridge is OK or not

 

[paul_374300602]

It looks like I'd best recheck my wires in the morning. I'll get back tomorrow.Thanks to all

Paul

 

[paul_374300602]

I rechecked all my wiring again, and finally disconnected the lot and just had the feed and earth connected to the relay. I still had a reading on both the battery and fridge feed even with the ignition off. I contacted the supplier to say it's a faulty relay and they said'oops some of my model were sent out without the instruction to tune the relay after fitting. There is a very small adjusting screw on the end of the relay and this has to be adjusted to trigger the relay at the correct voltage and disconnect when the voltage drops again when the engine is turned off.It now does what it should. So it wasn't me after all. Thanks to all,Paul

Paul

 

[WatsonJohnG]

Glad that you got it sorted

 

[runnerphil]

It wasn't Towsure by any chance was it? I had the same problem with the Self-Switching Combination Relay part W28. The tech on the phone/email was very good and soon helped me solve the problem.

 

[paul_374300602]

It wasn't Towsure by any chance was it? I had the same problem with the Self-Switching Combination Relay part W28. The tech on the phone/email was very good and soon helped me solve the problem.

Yes it was. But their technical man was very helpful.